Italian Prime Minister Silvio Berlusconi's government has narrowly won a crucial parliamentary confidence vote, which had been called after a bitter split within the ruling coalition.

In the second and most dramatic vote, deputies cheered loudly as Berlusconi survived a no-confidence motion by three votes in the lower chamber (314-311), where the 74-year-old leader's government no longer holds a secure majority.

Voting was briefly interrupted after scuffles broke out between rival camps during the tense session.

The government earlier in the day won a comfortable majority in the Senate, 162-135.

Defeat in either house would have forced Berlusconi to resign.

Despite Berlusconi's victory, observers say the future of his center-right government remains uncertain. His thin majority in the lower house will make it difficult for him to pass legislation, and Italy may have to go to elections before the government's mandate runs out in 2013.

As lawmakers cast their votes, tens of thousands of anti-Berlusconi protesters marched through Italy's big cities, from Palermo in Sicily to Turin in the north. In the capital, Rome, police fired tear gas as protesters hurled bottles and firecrackers.

Coalition Split

Today's votes follow a split between Berlusconi's ruling coalition and several dozen lawmakers led by former ally and parliament speaker Gianfranco Fini in July.

Defectors say Berlusconi has failed to implement the center-right policy platform on which the government was elected. They also say they can no longer tolerate a prime minister immersed in personal scandal and corruption allegations.

The aftermath of today's votes will be closely watched by financial markets on alert over the eurozone debt crisis. Italy's public finances are strained by a public debt burden of nearly 120 percent of gross domestic product.

Ahead of the votes, the billionaire media tycoon urged lawmakers on December 13 not to jeopardize the government for narrow political interests -- and promised to include in his government a broad coalition of moderates if he survived the vote.

"We need operational continuity, a perfectly functioning government, wide institutional and political cooperation, and we need to have the capacity to take decisions," Berlusconi said. "We need everything except a crisis in the dark."

Berlusconi's political career has in the past survived a series of legal actions -- including bribery and corruption probes -- and scandals over his relationships with women, wining three elections since gaining power for the first time in 1994.

In November, he was embroiled in a scandal over a 17-year-old dancer who was released from police custody after his personal intervention. He denied any improper conduct, saying he had simply pitied her plight.